LUMINESCENCE QUENCHING AND SENSITIZATION IN ARYL KETONE-TRIS(2,2'-BIPYRIDINE)RUTHENIUM(II) CHLORIDE SYSTEMS - EVIDENCE FOR A MIXED QUENCHING MECHANISM

A series of aryl ketones have been examined as triplet sensitizers of Ru(bpy)32+ in acetic acid solution. Only a few of them have been found to sensitize the phosphorescence of the acceptor. Spectroscopic behavior indicates that only those ketones with n,π* or π,π* lowest triplet levels are sensitizers. The results obtained combining lifetime and intensity quenching data demonstrate that a mixed quenching mechanism is operative, probably implying an upper excited state of the donor. Kinetic and photophysical parameters for the excited ketones in acetic acid are reported. © 1979 American Chemical Society.